#!/usr/bin/perl

use POSIX qw/floor/;
use bignum ;

#########################################################
#		Written by blackbox/motherbrain		#
#		Think outside the box :)		#
#							#
#		This is for people interested in	#
#		hashing algorithms			#
#		SHA algorithms are a little bit		#
#		Better the md5 my eyes			#
#		At least the 512bit one :)		#
#		Under the NFPL license			#
#							#
#########################################################


# function that takes a number and return true if it is prime
# false other wise
sub isPrime
{

if( $_[0] == 2 )
{
	return true ;
}

for ( $k=2 ; $k < $_[0] ; $k++ )
{

if( ($_[0] % $k) == 0 )
{

return false ;
}

}

return true ;
}

#Gets the first N primes
sub getPrimes
{
$N=$_[0] ;
$i=0;
$j=2;
@primes ;

while ( $i < $N )
{

if( (isPrime $j ) eq true ) {
  push( @primes , "$j") ;
  $i++;
  }
  $j++;
}

return @primes ;
}

#function for displaying the N primes
sub printPrimes
{
	@p = @_ ;
	for( $i=0 ; $i < ($#p + 1) ; $i++ )
	{
		if( $i == $#p )
		{
		print "@p[$i]" ;
		return ;
		}
		print "@p[$i] ," ;

	}

}

sub cuberoots
{

 @p = @_ ;
 for( $i = 0 ; $i < 64 ; $i++ )
 {

 $tmp = Math::BigFloat->new(@p[$i] ) ;

 $tmp = $tmp->broot(3) ;
 @p[$i] = $tmp ;

 }

 return @p ;

}

sub frac2hex
{
	$num = $_[0] ;
	$N = $_[1] ;
	$t = rindex($num , ".") ;
	$num = substr( $num , $t ) ;
	$const = Math::BigFloat->new(2) ;
	$const = $const->bpow($N) ;
	$BNUM = Math::BigFloat->new($num) ;
	$tmp = $BNUM->bmul($const) ;
	$tmp = $tmp->bfloor($tmp) ;
	$tmp2 = Math::BigInt->new($tmp) ;
	$hex = $tmp2->as_hex() ;

	return $hex ;

}

sub arrayfrac2hex
{
	@s = @_ ;
	for( $i=0 ; $i< ($#s + 1) ; $i++ )
	{
		@s[$i] = frac2hex( @s[$i] , ($#s + 1) ) ;
	}

	return @s ;
}

Math::BigFloat->precision(70);	# Precision
Math::BigFloat->accuracy(70);	# Accuracy

print "SHA Constant calculator \n" ;
@pn = getPrimes(64) ; # change the value to 64 , 80 or whatever many primes to get :)
print "Please wait may take sometime...\n" ;
@c = cuberoots @pn ;

print "\nPrimes are \n" ;
printPrimes @pn;

print "\nCubic roots of those primes are \n" ;
print @c ;

print "\nHex values for the fractional parts of the cubic roots of primes\nSHA constants for 384, 512 :) \n " ;
@w = arrayfrac2hex @c ;
print "@w  " ;